Method of preparing a metal dowel to receive molded resilient material



June 22, 1965 J. a. WHITTED AL 3,189,993

METHOD OF PREPARING A METAL EL TO RECEIVE MOLDED RESILIENT MATERIALOriginal Filed Sept. 22, 1960 2 Sheets-Sheet 1 F151 FE z June 22, 1965J. B. WHlTTED ETAL METHOD OF PREPARING A METAL DOWEL 'I'O REGEIV 2Sheets-Sheet 2 MOLD Original Filed Sept. 22, 1960 United States PatentMETHOD OF PREPARING A METAL DOWEL TO The present invention has to dowith a method of preparing a metal dowel to receive molded resilientmaterial and more particularly relates to the method as applied to asteel dowel used to support a resilient rubber-like material comprisingthe heel lift of a ladies high heel shoe.

This application is a continuation of our co-pending application S.N.57,733, filed September 22, 1960, now abandoned and entitled Method ofPreparing a Metal Dowel to Receive Molded Resilient Materia In recentyears ladies shoe styles have tended to smaller and smaller heelsections so that the high heels of fashionable shoes have presently alift of about inch square. The lift, of course, is of the usualconfiguration generally having fiat or slightly concave surfaces at thefront and a rounded rearward part matching the contour of the heel andcomprising an extension of the outer decorative surface of the heel.Great difficulty has been experienced in securing an adequate bondbetween lift material and a metal dowel which is driven into the heellengthwise to reinforce the heel as well as to support the wear surfaceprovided by the lift material. Various bonds have been attemptedincluding adhesive materials and mechanical bonds. Neither has provensatisfactory during walking, as a lady places considerable stress uponthe very small section of the heel lift. The tendency to tear the heellift loose is quite great. Normally headed dowels are generallyineffective for the reason that the resilient material inherently hasthe ability to part sufficiently to pass over the head. A nail-headshape thus may pull out of resilient material because the material giveseasily to slip past the head. The construction of the dowel inaccordance with the present invention obviates the difficultiespreviously made.

The principal object of this invention is to provide a new and improvedmethod of making a dowel for a heel lift as described.

Another object is to provide an improved method of making a dowel of thecharacter described which permits the dowel to sufficiently compete inproduction cost with previous constructions.

Another object is to provide a method of making a dowel suitable toautomated procedures.

A further object is to provide novel methods of making a dowel which mayresult in a structure more effective to retain resilient material moldedto the dowel.

Other objects, features and advantages of the present invention will beapparent from the following description of a preferred method involvingthe invention and as illustrated in the accompanying drawings in which:

FIGURE 1 is a diagrammatic sectional view through the parts of anappropriate die illustrating the first step in the invention.

FIGURE 2 is similar to FIGURE 1 showing the die and hammer in closedposition.

FIGURE 3 is a plan view of the piece part following its head in the dieof FIGURES 1 and 2.

FIGURE 4 is an illustration of the piece part in plan showing a furtherstep in its manufacture.

FIGURE 5 is a plan view illustration showing a drilling step of theinvention.

FIGURE 6 is a plan view of the piece part showing in dotted outline thelocation of the molded resilient material in the finished heel lift.

FIGURE 7 is an enlarged horizontal sectional view through the dowellooking toward the head showing the dowel in its condition when removedfrom the die.

FIGURE 8 is a fragmentary illustrational view of the head of the dowelfollowing the method step illustrated in FIGURE 5.

FIGURE 9 is a bottom plan view of the dowel as it appears in FIGURE 8.

FIGURE 10 is a sectional view through the dowel taken substantiallyalong line 10-10 in FIGURE 9.

FIGURE 11 is a horizontal sectional view through the dowel lookingtoward the head taken substantially along line ill-11 in FIGURE 8, and

FIGURE 12 is a view of the dowel substantially like I :7

FIGURE 7 looking toward the head.

The material of which the dowel is formed is a straight round steel wirestock from which a length is 'cut to form a blank 15 suitable forinsertion into a heading die 16 so that the blank rests upon a knock-outpin 17. The hammer i s associated with the die is provided with a roundcentering punch 19 adapted to penetrate the flat upper end 20 of theblank 15 providing a center for a later drilling operation. The die hasa cavity21 into which the steel material of the upper end of the blank15 is caused to flow forming an enlarged head of particularconfiguration. In FIGURE 2 a head 22 is shown as formed upon the blank15 and the hammer 18 has been caused to close upon the die 16. In someinstances the steel blank may be raised in temperature above ambient inorder to aid the flowability of the upper end of the blank into thecavity 21.

Once the dowel has been headed it is removed from the die and rolled atthe opposite end 23 to provide a slight taper. In the same or separaterolling step, a longitudinal extending knurl 24 may be added to the stemof the dowel to give the dowel a means of gripping the heel materialinto which it may be driven.

The particular form and shape of the head on the dowel resulting fromthe heading operation is particularly important. Referring to FIGURES 7and 12, it may be observed that the head has an outer circular flange 25joined to the stem 26 by three post-like bosses 27 extendinglongitudinally of the dowel. At the juncture of the dowel stem 26 andhead 22 a smaller flange 28 is present and used in a later molding stepto shut off communication through the mold with the cavity for the stem26. The surfaces or sides 29 extending between the post bosses 27 aregenerally arcuate and are seen in FIGURE 7 as a line since the surfacesextend longitudinally of the dowel. The posts 27 are arranged at thecorners of an equilateral triangle and the surfaces 29 generallyapproximate the sides of the triangle although they are slightlyarcuate. The distance between the center of the dowel and the surfaces29 is accurately controlled by the configuration of the cavity 21 in thedie so that each such surfaces has equal distance from the center of thedowel. Referring particularly to FIGURE 12, the drill centering cavity39 is also centered on the center line of the dowel.

Following the steps in the method previously described the dowel isautomatically chucked in a screw machinetype of operation in order thatthe head may be hollowed out by a drilling operation. Referring toFIGURE 5, a drill 311 is caused to enter the head 22 so that the axis ofthe drill and the center line of the dowel are co-linear. The drill iscaused to penetrate the head a sufficient distance to remove the metalcomprising the sides 29 of the head so that the openings occur betweenthe posts 27 above the circular outer flange 25. For example, it hasbeen found, working with a wire stock of about .132 inch in diameter,that a drill about .020 inch in greater diameter than the diameter of acircle including the surfaces 29 will be sufliciently large to removethe metal of the surfaces 29 without leaving burrs which are difiicultto remove by tumbling. Referring particularly to FIC- URES 811, it maybe noted that the drill is extended to the bottom surface 32 in the headleaving considerable connecting metal between the stem 26 and the headitself. A window 33 is formed between each pair of posts 27 and thedrill removes the metal along a circular bore 34 such that when viewedfrom the open end of the head there is visible clearance between theinner surface of the lower circular flange and the outer surface 35 ofthe flange 23 next to the stem 26.

Following the drilling operation, the dowel is ready to receive aresilient material molded about the head as illustrated in the dottedoutline of FIGURE 6. The resilient material would take the form of ablock 4t} which may be accurately shaped to the shape of the finishedlift \b ut ordinarily is over-sized for trimming on the shoe ass'rnblyline. The material extends'into the longitudinal bore in the head andthrough each of the windows 33 so that 1 's mechanically locked into thehead. The upper surfac 36 of the lower flange 25 provides aconsiderablearea rxsist-ing the pull which might be applied tending toremove tine material endwise frornthe dowel. Twisting of the materi'aLofthe lift relative to the dowel is adequately resisted by the materialextending through the'windows 33. The lift may-be worn down to thelouter flange 25 without materially lessening the effectiveness of theheel lift. The posts 27 are sufficiently strong to support the weight ofa lady resting directly on thei lower flange 25. I

The steps used to manufacture the dowel are primarily intended to behandled by automatic machinery. The cost of the dowel is thus held to aminimum and is 'competitive with other heel lift structures whileproviding a superior structure.

The foregoing detailed description has been given for clearness ofunderstanding only and no unnecessary limitations are to be understoodtherefrom, for some mpdifications will be obvious to those skilled intheart.

We claim:

1. The method of preparing a ladies heel lift comprising the steps of:enlarging one end of a wire stock to provide an enlarged first flange atthe extremity of one end of the stock and an enlarged head contiguouswith the flange and having spaced portions extending longitudinally ofthe wire stock, but spaced inwardly from the outer extent of saidintermediate portions; drilling lengthwise into said head past saidfirst flange with a drill of suflicient diameter to remove material onlyfrom the interior of said head including the intermediate portions ofsaid head, breaking through the outer extent of said intermediateportions to form a hollow head with lateral passages adjacent said firstflange between the exterior and interior of the head, said spacedportions of said head connecting said first flange and said secondflange and forming a cage structure for receiving a resilient materialwithin and around said head beyond said second flange; and moldingresilient material about the cage structure so that the molded resilientmaterial will pass between the spaced portions and on either side ofsaid first annular flange and about said second annular flange so thattwisting of the material from the dowel is restricted by the passage ofthe resilient material through the spaced portions and axial pull of thematerial from the dowel is restricted by said first flange.

2. The method of preparing a ladies heel lift comprising the steps of:enlarging one end of a wire stock to provide a first flange at theextremity of one end of the stock and an enlarged head contiguous withthe flange and having spaced portions extending longitudinally'of thedowel with the outer extent of said spaced portions generally alignedwith the outer extent of said first flange and the outer extent of theintermediate portions of the head between said spaced portions spacedinwardly from the outer extent of said flange, and a second flangepositioned between the head and said wire stock joining the head to thewire stock and extending outwardly from the wire stock with a generallyradial upper surface immediately adjacent the wire stock; drillinglengthwise into said head past said first flange with a drill ofsuflicient diameter to remove material only from the interior of saidhead including the intermediate portions of said head, to form a hollowhead with said first flange being annular and lfteral passages adjacentsaid first flange between the exterior and interior of the head, saidspaced portions of said head connecting said first flange with thesecond flange and forming a cage structure having open windows of a sizeto pass molded material through the windows from the exterior to theinterior of the cage, said window placement being adjacent the firstflange so that the molded material passing through the windows may bearagainst the first flange to hold the material against end-wisewithdrawal; and molding resilient material about the cage structure.

References Cited by the Examiner UNITED STATES PATENTS 1,699,953 1/ 29Conant 264-27 3 1,829,022 10/31 Stevenson. 2,389,517 11/45 Labadie29552.4 X 2,393,751 1/46 Chott 264--274 X 2,821,764 2/58 Leahy et a1.264--273 X WHITMORE A. WILTZ, Primary Examiner.

1. THE METHOD OF PREPARING A LADIES'' HEEL LIFT COMPRISING THE STEPS OF:ENLARGING ONE END OF A WIRE STOCK TO PROVIDE AN ENLARGED FIRST FLANGE ATTHE EXTREMITY OF ONE END OF THE STOCK AND AN ENLARGED HEAD CONTIGUOUSWITH THE FLANGE AND HAVING SPACED PORTIONS EXTENDING LONGITUDINALLYY OFTHE DOWEL WITH THE OUTER EXTENT OF SAID SPACED PORTIONS GENERALLYALIGNED WITH THE OUTER EXTENT OF SAID FIRST FLANGE AND THE OUTER EXTENTOF THE INTERMEDIATE PORTIONS OF THE HEAD BETWEEN SAID SPACED PORTIONSSPACED INWARDLY FROM THE OUTER EXTEND OF SAID FLANGE, AND A SECONDFLANGE POSITIONED BETWEEN SAID HEAD AND SAID WIRE STOCK JOINING THE HEADTO THE WIRE STOP, SAID SECOND FLANGE HAVING A CONTINUOUS OUTER EXTENDSPACED OUTWARDLY FROM THE PERIPHERY OF THE WIRE STOCK, BUT SPACEDINWARDLY FROM THE OUTER EXTENT OF SAID INTERMEDIATE PORTIONS; DRILLINGLENGTHWISE INTO SAID HEAD PAST SAID FIRST FLANGE WITH A DRILL OFSUFFICIENT DIAMETER TO REMOVE MATERIAL ONLY FROM THE INTERIOR OF SAIDHEAD INCLUDING THE INTERMEDIATE PORTIONS OF SAID HEAD, BREAKING THROUGHTHE OUTER EXTENT OF SAID INTERMEDIATE PORTIONS TO FORM A HOLLOW HEADWITH LATERAL PASSAGES ADJACENT SAID FIRST FLANGE BETWEEN THE EXTERIORAND INTERIOR OF THE HEAD, SAID SPACED PORTIONS OF SAID HEAD CONNECTINGSAID FIRST FLANGE AND SAID SECOND FLANGE AND FORMING A CAGE STRUCTUREFOR RECEIVING A RESILIENT MATERIAL WITHIN AND AROUND SAID HEAD BEYONDSAID SECOND FLANGE; AND MOLDING RESILIENT MATERIAL ABOUT THE CAGESTRUCTURE SO THAT THE MOLDED RESILIENT MATERIAL WILL PASS BETWEEN THESPACED PORTIONS AND ON EITHER SIDE OF SAID FIRST ANNULAR FLANGE ANDABOUT SAID SECOND ANNULAR FLANGE SO THAT TWISTING OF THE MATERIAL FROMTHE DOWEL IS RESTRICTED BY THE PASSAGE OF THE RESILIENT MATERIAL THROUGHTHE SPACED PORTIONS AND AXIL PULL OF THE MATERIAL FROM THE DOWEL ISRESTRICTED BY SAID FIRST FLANGE.